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Tilting Support Columns Force Closure of I-495 Bridge in Delaware

UPDATED -- The bridge that takes I-495 traffic the Christina River in Delaware was closed to traffic on Monday, June 2 after failing an inspection. The Delaware DOT closed the bridge at 6:00 p.m. There's no word yet on when it will reopen.

DelDOT received a report about an anomaly with a column late Friday. An inspection crew was sent out first thing Monday morning. An inspection showed four of the 37 support columns are tilted as much as four percent out of vertical alignment.

DelDOT is closing the bridge today because an inspection showed four of the 37 support columns are tilted as much as four percent out of vertical alignment.

Additionally, a DelDOT equipment operator reported a shifting of the concrete barrier on the road surface. After reviewing the data and pictures, bridge engineers recommended closure until further investigation could be done.

"The bridge is closed as of 6:00 p.m. today. This will cause a significant impact to the traveling public, and we are coordinating with local, state, and federal partners to provide information as we receive it," said a notice issued by the department "Our bridge engineers and consultant are on the scene and are placing tilt sensors to monitor the bridge."

Until further notice, I-495 will be closed northbound at Terminal Avenue and message boards are in place on I-95 and SR 1 and Rt. 13. Local northbound traffic can stay on I-495 to Terminal Avenue. I-495 southbound will be closed at the Pennsylvania State Line. Southbound traffic will be directed to take I-95 southbound, said an announcement from DelDOT Monday evening.

Bridge 1-813 over the Christina is a concrete deck on steel beams, built in 1974. It was last inspected in October 2012, and bridges of this type are inspected every two years. This section of I-495 carries approximately 90,000 vehicles daily, DelDOT says.

UPDATE

At a press briefing Tuesday afternoon, Delaware DOT officials said tilt monitors had been installed to measure any further movement. Over a 12-hour period, the monitoring data from the tilt sensors was inconclusive as to whether additional movement has occurred.

AECOM, DelDOT's bridge design consultant and geotechnical experts, are working together to try to determine the potential causes for the rotation of the support columns.

According to AECOM, their preliminary analysis shows the bridge can bear its own weight, but could exceed capacity under a full traffic load. This is why the bridge is closed.

Pennoni Associates has been inspecting the overall bridge and so far no other distress to the structure is evident.

The bridge will remain closed indefinitely. DelDOT will be setting up a field office and providing frequent updates on the status of the closure. We are working with the Federal Highway Administration to determine if emergency relief funding is available.